Re: avconv mov to flv

Can you post the full command and terminal output from the command that does not resize the video? As an aside I should mention that there would not be any problem using FFmpeg itself particularly if you used a modern version of it:

Today in my short 38 second video test. The second Flash video doesn't seem jerky, so I guess it is OK.

I'm curious why you would recommend FFmpeg over avconv? I'm not really a "serious" video converter, I'm not ripping DVDs. I am taking video from an iPhone and another digital camera and putting it on the web. The video is of our kids and I post them so both sets of Grandparents can view them.

So, why not just use YouTube, you ask? Well, it seems that the Grandparents in Japan have had a really big problem with YouTube lagging and they say it's easier to view if I put the videos on my site. I've tried a few different formats and the flv that I'm using seems to load the quickest and has OK quality.

I'm just flying by the seat of my pants here, so any advice from someone who actually knows what they are doing would be much appreciated.

Re: avconv mov to flv

There are much more skilled FFmpeg users on these Forums than myself but perhaps I can make a few observations:

Firstly I note that your original file contains h264 video and aac audio both of which actually live quite comfortably in a flv container. When you accept the FFmpeg/avconv defaults you actually get flv video and mp3 sound in an flv container, not a great problem but just be aware that you could probably just transfer the existing codecs to a new container. I see from your post that you have already experimented a little with this and other containers.

If your copy of avconv has access to the video filter scale perhaps try something like:

and add any necessary embellishments to the commandline as required. This may be enough to get decent quality sound and video and certainly the syntax I have suggested with the scale filter should resize things nicely. (The -1 for height resizes as appropriate to maintain the aspect ratio.) Experiment a little with the video -q:v 5 setting until you are happy, a setting of 1 will be very high quality while a setting of 21 would be very low quality.

As for suggesting FFmpeg there are several reasons:

A lot of the expert help on these Forums, and I do not include myself in this in this group of experts, comes from people using FFmpeg rather than avconv, including the maintainer of the guide I mentioned.

It is better to use a cutting edge copy of FFmpeg/avconv rather than the repository offering and there is only an FFmpeg guide for this purpose.

You and I would then be using the same version of FFmpeg and there would be no discrepance in terms of syntax, fiters etc.

When the big fork occurred I fell down on the FFmpeg side

Let me know how you go with this, hopefully this will make the grandparents happy

Last edited by andrew.46; January 1st, 2013 at 12:29 AM.
Reason: Removed some unnecessary comments, apologies to all...

Re: avconv mov to flv

Originally Posted by andrew.46

As for suggesting FFmpeg there are several reasons:

A lot of the expert help on these Forums, and I do not include myself in this in this group of experts, comes from people using FFmpeg rather than avconv, including the maintainer of the guide I mentioned.

It is better to use a cutting edge copy of FFmpeg/avconv rather than the repository offering and there is only an FFmpeg guide for this purpose.

You and I would then be using the same version of FFmpeg and there would be no discrepance in terms of syntax, fiters etc.

When the big fork occurred I fell down on the FFmpeg side

Let me know how you go with this, hopefully this will make the grandparents happy

Alrighty then, those reasons make sense to me. Plus the guide is so well setup that even a hobbiest like myself can follow the steps to compile and install the dev version of ffmpeg.

So if I want to go from .mov to .flv at 320x240 with audio at 22050. What would the command be?

Also on another note, some of our video comes from a camera that shoots mpg files. I've been combining all the mpg files into one using the cat command.

Code:

cat video1.mpg video2.mpg > output.mpg

I've noticed that in Movie Player the output.mpg only plays as far as the fisrt video in the sequence. In VLC, however, the entire output video will play, but it only displays time for the length of the first segment - thereafter the video continues to play as it should except the time has stopped moving forward.

Re: avconv mov to flv

So if I want to go from .mov to .flv at 320x240 with audio at 22050. What would the command be?

Just add that into the audio line:

Code:

-c:a libmp3lame -q:a 3 -ar 22050

Bear in mind that you only specify the width of the output image, avconv decides on the height while maintaining the aspect ratio.

Also on another note, some of our video comes from a camera that shoots mpg files. I've been combining all the mpg files into one using the cat command.

Code:

cat video1.mpg video2.mpg > output.mpg

I've noticed that in Movie Player the output.mpg only plays as far as the fisrt video in the sequence. In VLC, however, the entire output video will play, but it only displays time for the length of the first segment - thereafter the video continues to play as it should except the time has stopped moving forward.

Is this normal?

I have not had much to do with concatenating videos although it sounds from your example that there are some pitfalls . Have a look here for some guidance:

Re: avconv mov to flv

Originally Posted by GrouchyGaijin

Thanks, that brings up another question. What is demuxing? (What is the concat demuxer?)

I am sorry, I suspect I am making things a little too complex . A demuxer (= demultiplexer) extracts individual streams and sends them for encoding. The concat demuxer looks like it really should not be needed in your case as mpg files should join with cat. In the case where file level concatenation can be used the docs suggest you still can use the concat protocol as follows:

Re: avconv mov to flv

I recommend using libx264 instead of flv1 for flv container if possible. flv1 is not great, and just about everyone these days uses H.264 instead. You can get decent results with flv1, but it will require more bitrate for a similar quality which means a larger file size.

Your foo.mov contains AAC audio which can simply be copied into the flv file as Andrew mentioned. Same for the video stream, but a 25 MB video stream for a 38 second video may require re-encoding to get a more manageable size depending on your viewer's bandwidth.

Re: avconv mov to flv

Originally Posted by FakeOutdoorsman

I recommend using libx264 instead of flv1 for flv container if possible. flv1 is not great, and just about everyone these days uses H.264 instead. You can get decent results with flv1, but it will require more bitrate for a similar quality which means a larger file size.

Your foo.mov contains AAC audio which can simply be copied into the flv file as Andrew mentioned. Same for the video stream, but a 25 MB video stream for a 38 second video may require re-encoding to get a more manageable size depending on your viewer's bandwidth.